Utah Agricultural Experiment Station

A representative forage sample of ingested material is necessary in order to detect nutritional deficiencies on pasture and range lands and to obtain nutrient intake of grazing animals in conducting field digestibility trials. Collecting samples of forage representative of the grazing animal's diet is a complex problem since animals often select plants and plant parts from a mixture of species. The selectivity of the animal may vary with species of animal, available plants, stage of maturity, intensity of grazing, and weather conditions. Three methods have been used successfully in obtaining forage samples representative of ingested material under pasture and range conditions. They are namely: (1) hand plucking, (2) harvesting before and after grazing, and (3) sampling from fistulated animals. This method involves collecting material representative of forage being consumed from each plant species several times during the grazing trial. This can be accomplished by observing grazed plants or grazed portions

The potato psyllid was originally described and figured as Trioza cockerelli by Sulc (12) in 1909.

Negative transport is the downward conduction of water in the plant. This phenomenon has been studied by several investigators, yet considerable controversy about several aspects of the problem still exists. The portion of the leaf through which water enters is obscure. Meidner (16) suggested that specialized epidermal cells of the plant, Chaetachme aristata were involved in the phenomenon. Gessner (8) decided that most of the water was absorbed directly through the cuticle. Most investigators (4, 23) have considered that no water enters through the stomates (except perhaps a small amount of water vapor). Breazeale, McGeorge, and Breazeale (2, 3) investigated the absorption of water by leaves and its subsequent transport through the plant to the soil surrounding the roots. They concluded that tomato plants could grow to maturity, flower, and set fruit with no other source of water than that absorbed through the leaves from an atmosphere of 100 % humidity. They demonstrated that tomato plants can absorb water from a saturated atmosphere, transport it to the roots, and build up the soil moisture to or above the field capacity. Other investigators repeated the experiments of Breazeale but could get no evidence of actual water secretion by roots (9, 10, 25). Stone, Shachori, and Stanley (22) concluded that negative transport occurs only when the temperature is allowed to fluctuate and is caused by vapor pressure gradients and not by any active secretive force within the plant itself. Slatyer (20, 21), who reviewed these studies, stated that the main reason for lack of transport into soil is lack of an adequate gradient. The movement of water in plants has been studied from two different approaches: I. Some investigators have considered the entire soil-plant-atmosphere system (1, 6, 19, 24). They applied an analogue of Ohm's law and showed that water transport is controlled by the potential difference across the section and the resistance within the segment. This theory also proposes the important consideration that the rate of movement is governed by the point or region of greatest resistance in the system. Those who have studied this theory agree that the greatest resistance under natural conditions is usually located at the leaf-atmosphere interface where the water is converted from liquid to vapor. Most of these studies seem to be based more upon theoretical arguments than direct experimental results. II. Other scientists have investigated the movement of water in plants by studying some particular part of the system, such as the flow of water in the roots, leaves, or stem. Resistance to water flow in the conducting tissue of the stem is generally considered to be small as compared to other parts of the plant (5, 13, 15, 17). Some researchers have found the resistance in the roots is much larger than in the stems (12, 13, 14). Others have observed that the resistance in leaves is larger than in stems and roots (26). The resistance in the vascular elements can become larger when very small diameters are encountered (7, 27). It has also been indicated that the resistance to water flow is uniform through the cell walls, membranes, and vacuoles of plant tissues (1, 19). The experimental evidence to support these concepts is meager and inconclusive. Experimental measurements of the relative magnitude of the resistance of the stem, leaves, and roots to water flow in the absence of a water phase change have been made. This gives evidence of the relative contribution of the several plant parts to water flow resistance without the complicating factor of vaporization. Once this contribution to water flow resistance is known then studies can be made to combine the vaporization and vapor diffusion resistance as well as the soil resistance to water flow to the absorbing root surface. These experiments have also produced some information about negative transport.

The allometric relationship between plant volume and phytomass of crested wheatgrass was studied for the 1981, 1983, and 1984 growing seasons in west-central Utah. Basal diameters, canopy diameters, and standing plant heights were measured for individual plants. Three models of volume (basal elliptical cylinder, canopy elliptical cylinder, and elliptical cone section) were tested as predictors of plant phytomass using nonlinear regression. Elliptical cone section produced the highest R2 and lowest SEE, but requires measurement of canopy diameters which may be subject to excessive measurement error. Basal elliptical cylinder produced R2 and SEE values nearly comparable to those of the elliptical cone section; moreover, this model does not require measurement of canopy diameters, making it the practical choice. Nonlinear regressions for plants by size class (small, medium and large) were produced using 1983 data. Predictive ability of size class-specific equations was compared to that of the equation for all size classes combined. When phytomass of only small or medium size class plants was predicted, the SEE of size class-specific equations was slightly lower than the SEE of the equation for all size classes combined. When phytomass of plants from all size classes was predicted, however, the equation for all size classes combined produced the lowest combined SEE for new data (i.e., data not used to generate the equation). There were substantial year-to-year differences between equations, which indicates the necessity of producing new equations each year.

During the winter of 1956–57 a series of grazing trials was conducted on the desert of west-central Utah to determine the practicability of using sheep equipped with esophageal-fistula cannulae for collecting diet samples. The fistulated animals were grazed in inclosures for trial periods of six to eight days. There were seven such trials, each located on a different vegetation type. Diet samples were collected daily from the animals and analyzed chemically. Diets for each trial were also determined by hand plucking vegetation samples representative of the forage being consumed. A comparison of the chemical content of diets obtained by fistula and hand plucking shows differences to be statistically significant for all constituents except ether extract, total protein, and cellulose. The greatest differences were found in ash and phosphorus. Correcting the fistula samples for ash and phosphorus contributed by saliva during collection is desirable even though the nutritive content is changed only slightly.

A new technique for collecting herbage samples by means of sheep equipped with esophageal-fistula cannulae is described. Several fistulated sheep were used to collect forage samples representative of ingested material. Other sheep were used in the experimental areas to collect liquid and solid excreta by means of collection bags. Thus by using the lignin-ratio procedure the digestibility of range forage can be determined.

Summary A curd test has been developed whereby the degree of hardness of the curd of cows’ milk can be determined. By means of this test the dairy herd of the Utah Agricultural College has been classified on the basis of the curd character of the milk. This classification extends over a period of more than six months and includes cows in all stages of lactation. As a result of these studies it has been shown that each cow had an individual milk curd character that was fairly regular throughout her entire lactation period, but in general it hardened during the first part of the period to soften again toward the latter end of the normal lactation period. The curd tension of the harder curded milk was sometimes as much as 10 times as great as the curd tension of the softer curded milk. The individual difference in curd character was independent of breed and fat content of the milk. The Jersey breed as an average, however, had a much harder curded milk than the Holstein breed, yet some of the Jerseys had a softer curded milk than the harder curded Holsteins.

Most important nutrients in appraising the value of range forage are: digestible protein, productive energy, phosphorus and carotene (vitamin A). Accurate appraisals of these constituents are needed for determining deficiencies of range forage, compounding supplements for range feeding, and for comparing the value of the various range plants. Generally, the ranges of the intermountain area do not produce forage that furnishes all the dietary needs of grazing animals during the winter grazing season. For optimum nutrition, supplementary feed must be supplied, and the amount and nature will depend upon the quality and quantity of forage consumed. Livestock operators in this area prefer to feed home-grown supplements, such as corn, barley and alfalfa which are relatively high in carbohydrates, rather than expensive protein supplements that must be shipped long distances. Therefore, it is important to evaluate the energy-supplying qualities of range forage rather accurately so that feeds prodiced at home can be used to a maximum.

A study to determine differences in the botanical composition, nutritive content and digestibility of diets of cattle and sheep grazing singly and in common on sagebrush-grass and aspen ranges was conducted on northern Utah mountain ranges during the summers of 1963 and 1964. Six study areas of each vegetation type were selected and fenced into three enclosures, allowing proportionate amounts of herbage per animal-unit-day grazing to obtain comparable use of preferred forage classes by cattle and sheep. Two of the enclosures were grazed singly by cattle and sheep, and a third enclosure of combined size of the other two was grazed by the animals in common. Experimental animals were equipped with esophageal-fistula cannulae. A 5- to 6-day digestion trial was conducted during each grazing period. Digestibility was determined by the lignin-ratio technique. Cattle preferred grasses, while sheep preferred forbs and browse. Utilization of grasses by both cattle and sheep decreased and preference for browse increased as the season advanced. Utilization of the primary herbage species under common use was found to be, in most instances, intermediate to the single-use values for cattle and sheep. Therefore, it was concluded that if utilization of the primary forage species were allowed to reach the equivalent under single use, additional animal-days of grazing per acre would be realized under common use as compared to single use by either kind of animal. Cattle diets were higher in cellulose, but sheep diets contained more total protein, lignin, other carbohydrates and phosphorus. Sagebrush-grass range yielded diets higher in total protein, lignin and gross energy, but lower in ether extract and the other carbohydrates compared to aspen range. Cattle digested cellulose, ether extract and gross energy better than sheep and had more DE and TDN in their diets. Digestion coefficients for ether extracts, other carbohydrates and gross energy were higher for diets on aspen range. These diets also contained more DE and TDN than diets on sagebrush-grass range. Grazing systems did not significantly influence the digestibility of any nutrient studied, nor did they influence the level of any digestible nutrient.

During the winter grazing season of 1950–51 a study was conducted on desert ranges in northwestern Utah to compare two methods of determining forage consumption and digestibility of native forage species by the use of tracer or indicator plant substances. The one method uses lignin as the indicator substance and is known as the lignin ratio technique. The other method involves plant pigments as the indicator substance and has been termed the chromogen method. Wether sheep equipped with specially constructed fecal bags were allowed to graze temporary enclosures on native forage types composed of single species. Forage samples were taken by careful observation of grazing animals and hand plucking forage comparable to material actually being consumed. The ratio of the various constituents to either lignin or chromogen material in the forage and feces was the basis for determining digestibility. It was found that both lignin and chromogen content could be determined chemically with equal accuracy. However, the coefficient of variation for digestibility among animals was much smaller by lignin determinations than by chromogen determinations. Forage consumption as determined by the lignin ratio technique agreed rather closely with calculated dry matter intake commonly accepted for the various sizes of sheep. Calculated digestibility of dry matter by the use of lignin as the indicator substance compared favorably with digestibility results obtained by other investigators on similar forages. This was not generally true for determinations made by the chromogen method. It was concluded that the chromogen method was not suited for determining digestibility of winter range forage since, in some cases, there was considerably less chromogen material recovered in the feces than was actually consumed.

Journal Article HYBRIDS BETWEEN AGROPYRON REPENS AND AGROPYRON DESERTORUM Get access DOUGLAS R. DEWEY DOUGLAS R. DEWEY Research Agronomist *Crops Research Division, A.R.S., U.S.D.A., Logan, Utah. Cooperative investigations of the Crops Research Division, A.R.S., U.S.D.A., and the Utah Agricultural Experiment Station, Logan, Utah. Approved as Journal Paper No. 130, Utah Agricultural Experiment Station Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Heredity, Volume 52, Issue 1, January-February 1961, Pages 13–21, https://doi.org/10.1093/oxfordjournals.jhered.a107013 Published: 01 January 1961

Digestion trials were conducted on typical desert ranges in southern Utah to study the effect of intensity of grazing upon the nutritive content of a sheep's diet. Sixteen trials were conducted during the winter grazing season, October 1956, to March 1957. Sheep were grazed on two enclosures of approximately equal size. Four sheep were grazed in one enclosure, and eight in the other, Four sheep in each enclosure were equipped with bags for collection of feces. Forage samples of the parts of the plants being eaten by the sheep were collected daily. Digestibility coefficients and daily consumption were calculated by means of the lignin-ratio technique. Lignin in the diet increased in all trials as intensity of grazing increased. On pure stands, protein, gross energy, ether extract, and phosphorus tended to decrease as intensity of grazing increased. However, on some of the mixtures, a dietary change from one species to another, with increased intensity of utilization, increased the protein, phosphorus, and cellulose content of the diet. In most trials, the digestibility of the nutrients in the diet was considerably reduced by heavy grazing. Forage intake was markedly reduced by heavy grazing in all trials.

Esophageal-fistula cannulae were used successfully to determine the nutrient intake of sheep and cattle grazing in common on mountainous summer range in northern Utah. Forage samples for chemical analysis were collected from eight fistulated sheep and two fistulated steers. Fecal samples were collected by the grab method and digestibility was determined by the lignin-ratio technique. Cellulose and gross energy in the diets had higher digestibility by cattle than sheep. As a result, the digestible energy and total digestible nutrients were higher in the forage consumed by cattle compared to forage consumed by sheep. Percent total protein and phosphorus was higher in the forage selected by sheep than by cattle.

A method was developed for quantitative determination of miserotoxin, a poison in timber milkvetch ( Astragalus miser Dougl. ex Hook.). The presence and concentration of miserotoxin was determined in eight varieties of timber milkvetch. The seasonal variation in the concentration of the poison was followed in variety oblongifolius (Rydb.) Cron. Miserotoxin occurred primarily in the leaves with smaller amounts in the roots, flowers, and seeds. The poison level in leaves and stems decreased rapidly after seed dispersal. Miserotoxin was found in varieties oblongifolius (Rydb.) Cron., serotinus (Gray) Barneby, and hylophilus (Rydb.) Barneby, but was not found in varieties miser Dougl. ex Hook., tenuifolius (Nutt.) Barneby, crispatus (Jones) Cron., praeteritus Barneby, and decumbens (Nutt.) Cron. The three varieties containing miserotoxin were poisonous to 1-week-old chicks ( Gallus domesticus , Arbor Acre 50 × Vantress hybrids); the other five varieties were not poisonous.

Need for an understanding of the nutrition problems on the western range is of paramount importance. Despite the importance of this problem, little is known as to the actual composition of the grazing animal's diet. The reasons for this lack of knowledge are many fold, including (a) difficulty of collecting representative samples of vegetation because of soil, site, and seasonal variations, (b) difficulty of finding what species and portions of plants actually are consumed, and (c) difficulty in interpreting the nutritive content of the ingested forage. The method here presented for determining the nutritive content of the sheep's diet under range conditions is an entirely new approach to this problem and is based upon chemical analyses of the vegetation before being grazed as compared to chemical analyses after being grazed. Briefly, the method consists of collecting a predetermined number of plant units before grazing and a similar number after grazing. Each plant species is sampled both before and after grazing and each sample is weighed and chemically analyzed. The difference in weight and chemical composition between the before-grazing sample and the after-grazing sample serves as a measure of the nutrient content of the ingested forage. It was found from this study that sheep are highly selective in their diet and consume largely leaves and tender stems, rejecting the more fibrous parts of the plant. Consequently, a much better quality of forage actually makes up the diet than chemical analyses of bulk samples would indicate.

Abstract A micro method for cholesterol determination adapted from the macro method of Sperry and Webb is described with comparisons of results obtained by the two methods. In general, the two methods gave similar results for free and total cholesterol.

Sixteen methods of seedbed preparation and seeding three wheatgrasses in dense stands of cheatgrass were tested from 1 to 3 years (1961-62, 1963-64, 1964-65) on an 8.5-inch rainfall area near Wendell, Idaho. Averaging all years, deep furrow drilling in the fall gave the best stands, followed by fall cultivation and drilling and then by summer fallow and drilling. Herbicidal treatment followed by drilling was good the first year but was not consistent. Seeding success was in direct relation to the kill of cheatgrass.

Four 50 × 50 foot plots were sprayed with 2 lb./acre 2,4-D in 1959, 1960, 1965 and 1969 to kill fleshy-rooted, spring-growing plants and annuals. These plants are the major source of food for pocket gophers. Averaging the 10-year period, 1960-69, spraying reduced gopher mounds by 93% and winter casts by 94% when compared to the unsprayed areas.

Untreated alfalfa hay and hay dusted with technical DDT were fed to 16 Holstein cows during 2 years DDT appeared in the milk within 4 days after the feeding of DDT-treated hay and the amount gradually increased until a fairly constant level was reached. More DDT was found in milk and tissues of cows that consumed hay treated with higher levels of DDT. DDT persisted in the milk for 4 months and disappeared approximately 6.5 months after feeding of DDT-treated hay was discontinued.

This paper is the second of a series reported from the Utah Station on the transfer of dietary DDT to eggs and poultry tissues. The first paper was reported by Bryson et al. (1950) on the accumulation of DDT in poultry products. The published literature on this topic has been reviewed and reported by Bryson et al. (1950). EXPERIMENTAL THE alfalfa hay fed in this experiment was from the same field described by Harris et al. (1949). This alfalfa was dusted with 0, 1, 2, and 4 pounds of technical DDT per acre. The harvested hay was ground into meal and 15 percent of this meal was included in the laying mash. DDT was also added to a similar mash made from untreated alfalfa meal at levels of 0, 50, 100, and 200 p.p.m. These diets are reported in Table 1. The design of this experiment is as follows: A . . .